Valorization of agro-industrial wastes of sugarcane bagasse and rice husk for biosorption of Yellow Tartrazine dye.

The use of agro-industrial wastes as biosorbents is a promising alternative for sustainable, economical and effective adsorption. However, few studies evaluate the use of Brazilian agro-industrial waste as biosorbents without physicochemical pre-treatment. This study explored the potential of sugarcane bagasse (SCB) and rice husk waste (RHW) as low-cost biosorbents for yellow tartrazine dye removal.

Design and Optimization of Stimuli-responsive Emulsion-filled Gel for Topical Delivery of Copaiba Oil-resin.

This study presents a phytotherapeutic emulsion-filled gel design composed of Pluronic® F127, Carbopol® C934P, and high level of copaiba oil-resin (PHY-ECO). Mathematical modeling and response surface methodology (RSM) were employed to access the optimal ratio between the oil and the polymer gel-matrix constituents. The chemometric approach showed robust mechanical and thermoresponsive properties for emulsion gel.

Kinetic spectrophotometric method for real-time monitoring of ultraviolet photoreactions: A mini-photoreactor.

It is proposed a new approach to evaluate the performance of ultraviolet photoreactions by integrating UV-LED and a UV-Vis cuvette as a mini-reactor for kinetic monitoring in a spectrophotometer not influenced by external light. This system uses only 3.0 mL of solutions in a rectangular quartz cuvette with a mini-bar magnetic stirrer in a cell holder and a UV-LED of 5 W with λ at 370 nm was positioned on the top of the cuvette and maintained at 25.

Evaluation of the photodynamic activity of xanthene dyes on Artemia salina described by chemometric approaches.

The development of drugs for photodynamic therapy (PDT) is an important area of research due to their growing use in medical applications. Therefore, it is important to develop new bioassay methods for PDT photosensitizers that are inexpensive, easy to handle and highly sensitive to environmental conditions. Xanthene dyes (fluorescein, rose bengal B, erythrosine B and eosin Y) with LED light sources were investigated using Artemia salina as a bioindicator of photodynamic activity.

Antibacterial photodynamic therapy for dental caries: evaluation of the photosensitizers used and light source properties.

Photodynamic therapy studies have shown promising results for inactivation of microorganisms related to dental caries. A large number of studies have used a variety of protocols, but few studies have analyzed photosensitizers and light source properties to obtain the best PDT dose response for dental caries. This study aims to discuss the photosensitizers and light source properties employed in PDT studies of dental caries.

Self-aggregation processes of 1,6-diphenyl-1,3,5-hexatriene in water/ethanol mixtures with high water percentages.

This work describes the behavior of 1,6-diphenyl-1,3,5-hexatriene (DPH) in ethanol/water mixtures. The dependence of DPH photophysical properties (absorption and fluorescence emission) on the water percentage in ethanol indicates that DPH undergoes self-aggregation processes in solvent conditions above a critical water content. Evidence such as an additional absorption band, Beer's law deviation, kinetic behavior, and other experimental results obtained from temperature variation and surfactant addition demonstrated the presence of several types of DPH aggregates.

pKa determinations of xanthene derivates in aqueous solutions by multivariate analysis applied to UV-Vis spectrophotometric data.

Xanthenes form to an important class of dyes which are widely used. Most of them present three acid-base groups: two phenolic sites and one carboxylic site. Therefore, the pKa determination and the attribution of each group to the corresponding pKa value is a very important feature.